The present invention relates to balloon catheters and, particularly, to a balloon catheter having a plurality of balloon elements or lobes configured to support a portion of a blood vessel wall while providing a flow path to allow blood to flow past the balloon elements and perfuse the vessel.
Angioplasty has gained wide acceptance as an efficient and effective method of treating constrictions caused by undesirous tissue growth or lesions on the inner walls of blood vessels. Such tissue growth or lesions result in a narrowing ("stenosis"), which severely restricts or limits the flow of blood through the blood vessel. In the most widely used form of angioplasty, a catheter carrying a dilatation balloon is guided through the vascular system. With the aid of fluoroscopy, a physician is able to position the balloon across the stenosis. The balloon is then inflated by applying fluid pressure through an inflation lumen of the catheter to the balloon. Inflation of the balloon compresses the stenosis and opens the constriction to reestablish acceptable blood flow through the artery.
Occasionally, the need arises to temporarily support the arterial wall following dilatation of the artery. In some instances, this is occasioned by the formation of a flap in the inner artery wall. Such a flap, which is generally defined by a helical tear in the artery wall, may inhibit or restrict the flow of blood through the artery. In other instances, the need is brought about by a collapse or spasm of the artery. A variety of catheters are presently used for temporary support of the artery wall.
Prolonged occlusion of a blood vessel poses serious risk of damage to the tissue, downstream from the occlusion, which is deprived of oxygenated blood. This places a limitation on the length of time a balloon can remain expanded within an artery. Perfusing the artery while a balloon is inflated allows the balloon to remain inflated for an extended period of time. Also, since arteries may branch in the region occluded by a balloon, perfusion may provide a continuation of blood flow to the arterial side branches.
U.S. Pat. No. 4,581,017 issued Apr. 8, 1986 for CATHETER SYSTEMS in the name of Harvinder Sahota teaches a segmented or lobed dilatation balloon which forms blood flow passages between the balloon lobes. That is, the Sahota patent provides lobes positioned around the catheter body to provide a dilatation balloon while allowing blood to flow in passages formed by circumferentially adjacent balloon lobes. U.S. Pat. No. 4,983,167 issued Jan. 8, 1991 for BALLOON CATHETERS, also in the name of Harvinder Sahota, teaches, in FIG. 14, a one-sided dilatation balloon which provides a lower profile than a balloon that completely encircles the catheter body. The latter Sahota patent also discloses a multi-lobed dilatation balloon catheter.